The present invention is directed to a three dimensional structure for a photodetector device and specifically, to such a device constructed using dielectrically isolated silicon pathways to directly connect the top side of the photodetectors (photodiodes) on a substrate to a point on the bottom of the substrate.
Optical detectors typically include a one- or two-dimensional array of photodetectors provided on a front surface of a semiconductor die. The photodetectors typically generate charge in response to light that illuminates the front surface of the die. Optical detectors further include wiring and other electronic devices to address each photodetector on the die and read accumulated charge therefrom. The wiring and addressing devices typically are provided on the front surface of the die and block light. This wiring and addressing devices can impair performance of the optical detector. Accordingly, designers of optical detectors take great care to maximize the ratio of useful area of a die (the unblocked portion that can be used as photodetectors) to the total area of the die (both the blocked and unblocked portions).
The inventors perceive a need in the art to provide improved structures for photodetectors and, specifically, to provide a semiconductor die that avoids use of wiring and addressing devices on the front surface of the die.